a number of zeros are to be counted for calculating the total number of possible hosts per subnet.
$255-248 = 7$ can be represented using $3\;\text{bits}$
these $3\;\text{bits} + 8\;\text{bits}$ more $= 11\;\text{bits}$
So, possible subnets $= 2^{11}$ out of these $2$ are reserved as subnet $\text{ID}$ and $\text{DBA}$
Therefore, we have maximum possible usable hosts $= 2^{11}-2 = 2046$
Correct Answer: $C$